title: CT and MRI early vessel signs reflect clot composition in acute stroke.
abstract: OBJECTIVE
  The purpose of this study was to provide the first correlative study of the hyperdense middle cerebral artery sign (HMCAS) and gradient-echo MRI blooming artifact (BA) with pathology of retrieved thrombi in acute ischemic stroke.
  
  
  METHODS
  Noncontrast CT and gradient-echo MRI studies before mechanical thrombectomy in 50 consecutive cases of acute middle cerebral artery ischemic stroke were reviewed blinded to clinical and pathology data. Occlusions retrieved by thrombectomy underwent histopathologic analysis, including automated quantitative and qualitative rating of proportion composed of red blood cells (RBCs), white blood cells, and fibrin on microscopy of sectioned thrombi.
  
  
  RESULTS
  Among 50 patients, mean age was 66 years and 48% were female. Mean (SD) proportion was 61% (±21) fibrin, 34% (±21) RBCs, and 4% (±2) white blood cells. Of retrieved clots, 22 (44%) were fibrin-dominant, 13 (26%) RBC-dominant, and 15 (30%) mixed. HMCAS was identified in 10 of 20 middle cerebral artery stroke cases with CT with mean Hounsfield Unit density of 61 (±8 SD). BA occurred in 17 of 32 with gradient-echo MRI. HMCAS was more commonly seen with RBC-dominant and mixed than fibrin-dominant clots (100% versus 67% versus 20%, P=0.016). Mean percent RBC composition was higher in clots associated with HMCAS (47% versus 22%, P=0.016). BA was more common in RBC-dominant and mixed clots compared with fibrin-dominant clots (100% versus 63% versus 25%, P=0.002). Mean percent RBC was greater with BA (42% versus 23%, P=0.011).
  
  
  CONCLUSIONS
  CT HMCAS and gradient-echo MRI BA reflect pathology of occlusive thrombus. RBC content determines appearance of HMCAS and BA, whereas absence of HMCAS or BA may indicate fibrin-predominant occlusive thrombi.
authors.affiliation: UCLA Stroke Center, 710 Westwood Plaza, Los Angeles, CA 90095, USA. davidliebeskind@yahoo.com
authors.forename: David S
authors.initials: DS
authors.lastname: Liebeskind
authors.forename: Nerses
authors.initials: N
authors.lastname: Sanossian
authors.forename: William H
authors.initials: WH
authors.lastname: Yong
authors.forename: Sidney
authors.initials: S
authors.lastname: Starkman
authors.forename: Michael P
authors.initials: MP
authors.lastname: Tsang
authors.forename: Antonio L
authors.initials: AL
authors.lastname: Moya
authors.forename: David D
authors.initials: DD
authors.lastname: Zheng
authors.forename: Anna M
authors.initials: AM
authors.lastname: Abolian
authors.forename: Doojin
authors.initials: D
authors.lastname: Kim
authors.forename: Latisha K
authors.initials: LK
authors.lastname: Ali
authors.forename: Samir H
authors.initials: SH
authors.lastname: Shah
authors.forename: Amytis
authors.initials: A
authors.lastname: Towfighi
authors.forename: Bruce
authors.initials: B
authors.lastname: Ovbiagele
authors.forename: Chelsea S
authors.initials: CS
authors.lastname: Kidwell
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tateshima
authors.forename: Reza
authors.initials: R
authors.lastname: Jahan
authors.forename: Gary R
authors.initials: GR
authors.lastname: Duckwiler
authors.forename: Fernando
authors.initials: F
authors.lastname: Viñuela
authors.forename: Noriko
authors.initials: N
authors.lastname: Salamon
authors.forename: J Pablo
authors.initials: JP
authors.lastname: Villablanca
authors.forename: Harry V
authors.initials: HV
authors.lastname: Vinters
authors.forename: Victor J
authors.initials: VJ
authors.lastname: Marder
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Saver
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D001792:Blood Platelets / Q000000981:diagnostic imaging / Q000473:pathology; D004912:Erythrocytes / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D005337:Fibrin / Q000648:ultrastructure; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000473:pathology; D007962:Leukocytes / Q000000981:diagnostic imaging / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020521:Stroke / Q000000981:diagnostic imaging* / Q000473:pathology*; D017131:Thrombectomy; D013927:Thrombosis / Q000000981:diagnostic imaging* / Q000473:pathology*; D014057:Tomography, X-Ray Computed
chemical_list: D005337:Fibrin